Stabilized vinyl resin



Patented Dec. 30, 1941 STABILIZED VINYL RESIN Victor Yngve,

Lakewood, Ohio, assignor to Carbide and Carbon Chemicals Corporation, acorporation of New York No Drawing. Application September 17, 1940,

Serial No. 357,096

7 Claims.

The invention relates to stabilized vinyl resins and compositionscontaining the same. It is particularly concerned with new and improvedstabilizing materials which show definite advantages in preventingdeterioration of vinyl resins at elevated temperatures.

As synthetic resinous bodies vinyl resins are well known in the art, andtheir valuable properties as components of plastic compositions ofvarious sorts have been recognized. In the compounding and processing ofsuch resins into molded and extruded articles, or as constituents ofcertain coating compositions it is usually necessary to subject theplastics to certain degrees of heat. Under such conditions, as well asat elevated temperatures which may be encountered in normal usage, atendency toward deterioration is quite commonly encountered. To preventdecomposition in this respect it has, therefore, been consideredessential with known types of vinyl resin to incorporate therewithadditive materials adapted to exert a stabilizing action, and numerouscompounds have been suggested for this purpose.

The present invention is particularly concerned with vinyl resins of thetype which may be formed by conjoint polymerization of a vinyl halidewith the vinyl ester of an aliphatic acid, such as are described in U.S. Patent No. 1,935,577 to E. W. Reid. Within the broader class of theseresins, conjointly polymerized vinyl chloride and vinyl acetatecontaining in the polymer 60% to 95% of vinyl chloride, or other halide,are especially susceptible to stabilization by the compounds hereinafterdescribed.

In accordance with my invention I have found that alkyl derivatives oftin will function as excellent stabilizers for vinyl resins, and whenintimately dispersed therein will provide plastic compositions ofsubstantially improvedresistance to heat deterioration. A particularadvantage in these compounds, other than in their actual stabilizingfunction, also resides in the fact that resin compositions incorporatingthem show practically no tendency toward discoloration in the presenceof hydrogen sulfide, thereby presenting an especially valuableapplication of the materials in vinyl resin plastics which may becontacted with sulfur compounds.

Among the alkyl tin derivatives, those containing in the alkyl radicalthree or more carbon atoms are preferable. Typical of these are the tinorgano-metallic compounds containing the propyl, isopropyl, butyl,isobutyl, tertiary butyl,

like. A mixed alkyl grouping in the tin compound is also appropriate,which may include two or more difierent alkyl radicals in the molecule.Representative of specific compounds within thebroader classificationare those of the following formulae:

Throughout this specification, and the claims, the broadest scope of theinvention as defined by the class organo-metallic alkyl derivatives oftin is intended to include any or all of the compounds as aboverepresented.

As an example of the effectiveness of these new stabilizers a smallquantity of tetrabutyl tin was incorporated in a vinyl resin plasticcomposition. The resin employed was one formed by the conjointpolymerization of vinyl chloride and vinyl acetateand containing about87% of vinyl chloride. The tetrabutyl tin was intimately and thoroughlydispersed in the resinous mass by the various amyl, hexyl, octyl groupsand the milling on a heated two-roll mill. In subsequent processing atelevated temperatures the plastic did not darken. In practice 1 to 3% oftetrabutyl tin is preferred for incorporation in the resin.

Further experiments with vinyl resin compositions similar to the abovewere made, including as the stabilizer, others of the organo-metallicalkyl derivatives of tin set forth above. The results obtained showedimproved heat stability in all instances over plastic compositions ofsimilar v inlyl resin containing known stabilizing materia s.

To incorporate the stabilizer within the resin composition methodsheretofore known may be employed which will effect an intimatedispersion thereof throughout the resin mass. The amounts necessary toeffect desirable heat stability are also within a range heretofore foundsuitable with other materials, varying from about 0.5% to about 3.0% byweight of the vinyl resin. In the compounding of plastic compositionsfor various uses, there may be included any of the common solvents,plasticizers, pigments, and other modifying materials withoutdetrimental effect upon the heat stability afforded by these newstabilizers.

Modifications within the scope of the appended claims will be evidentand are intended to be included within the invention as defined therein.

This application is in part a division of my application Serial Number118,568, filed December 31, 1936, now Patent No. 2,219,463.

I claim:

, l. A heat-stable resinous composition compris ing a, vinyl resincontaining polymerized vinyl halide and a stabilizing material,said'stabilizing, 1 l material comprising an organic-metallic tetra-1'alkyl derivative'of tin. I I I 2,;A heat-stableresinouscompositioncomprisev ing a vinyl resin containing polymerizedvinyl" halide and a. stabilizing; material, said stabilizing materialcomprising an organo-metallic tetra,.- -v alkyl derivative of tin' inwhich the alkyl radicals contain at least threevcarbon atoms.

3. A heat-stable resinous composition comprisving a vinyl resincontaining polymerized vinyl halide and a stabilizing material, said,stabilizing material comprising an .organoemetallic mixed,

tetra-alkyl derivative of tin. 1

' 1 I I v I I 4. A; heat-stable resinous composition compris- Y ing avinyl resin 'of the type formed bythe conjoint polymerization of .a'vinyl halide with 'ai vinyl ester of an aliphatic acid and containing inthe polymer about 60%: to;95% of I the vinyl I I halide, and astabilizingmaterial intimately-dis i I I I I I persed therein,saidstabiiizing material compristin.

5. A heat-stable resinous composition comprising a vinylresinoi the'typeformed bythe conjoint polymerization of vinyl chloride with vinylacetate and containing in the polymer about 60% to 95% of vinylchloride, and a; stabilizing material intimately dispersed therein, saidstabilv izing material comprising tetrabutyl tin.

' 6. A'heatestable resinous composition compris ing a. vinyl resin oithe type iormed'by the'conv Joint polymerization of vinyl chloride withvinyl acetate: and containing 7 in the p lymer, about 60% t0 .95% ofvinyl chloride, and a. stabilizing material intimately dispersedtherein, said stabilizing' materialcomprisingtetraethyl tin. I 7-. Promsoi producing heat+stable resinous compositions which comprisesintimately mixing 7 a vinyl resin of the typeiormed by conjoint polynerization oi vinyl chloride with vinyl acetate I I I and containingabout 60% to 95% vinyl chloride VICTOR

